There are many applications for flexible sheet material having appropriate "breathing" qualities. For instance most articles of clothing, particularly gloves, shoe uppers and soles, and the like, must have appropriate breathing qualities to be useful. Natural leather, and other natural materials, have appropriate breathing qualities, but when it is desired to make useful articles out of synthetic material, the breathing qualities are usually not present.
According to the method of the present invention, it is possible to make flexible sheets of synthetic, or other thermoplastic materials that have appropriate breathing qualities so that they can be used in place of natural leather, or the like, in articles of clothing and for other useful articles that require significant breathing characteristics.
The method according to the invention is practiced by utilizing a mold elongated in a first dimension, and having a plan or cross-sectional shape corresponding to the desired shape of the sheet material articles being produced. Preferably the mold is oriented so that the first dimension is vertical. A plurality of strands of porous fibrous material, such as strands of natural material (e.g. cotton, wool, or the like) are hung from the top of the mold to extend in the first dimension. Then liquid thermoplastic material is poured into the mold.
After cooling of the thermoplastic material, a slab having a plurality of spaced strands extending therethrough results. The slab is then sliced in a dimension substantially perpendicular to the first dimension (i.e. substantially perpendicular to the dimension of elongation of the strands in the slab), to produce flexible sheets of material having the desired thickness.
The flexible sheets of material according to the present invention comprise thermoplastic sheets having a plurality of spaced breathing apertures extending through the thickness thereof, each breathing aperture filled with a porous fibrous material. The sheet material can be utilized in any application where breathing characteristics are necessary or desirable, and may have the configuration of a glove blank, shoe upper or sole, or other article of clothing.
It is the primary object of the present invention to produce flexible sheets of material having good breathing characteristics. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.